Safety knife



FIG. 1 is a perspective of the safety knife from front, right side and above;

FIG. 2 is a front view of the safety knife;

FIG. 3 is a top plan view of the safety knife;

FIG. 4 is a left side view of the safety knife;

FIG. 5 is a view of the safety knife from beneath;

FIG. 6 is a right side view of the safety knife; and,

FIG. 7 is a rear view of the safety knife. 

The ornamental design for a safety knife, as shown. 